In the prior art the clogging of hygroscopic fertilizer in the small tubes of applicators has been a costly unsolved problem.
The obtaining of relatively dry fertilizer does not solve this problem because moisture in the air is absorbed into the fertilizer even as it sits in the delivery hopper which is moved down the field on wheels. The clogging is greatest in humid weather.
An objective, therefore, is to make use of the heat generated in the hydraulic fluid flowing through the hydraulic motor that operates the fan so that this heat is placed in the air that the fan blows onto the fertilizer. In this way, a readily available and otherwise wasted source of heat is utilized by the use of an inexpensive heat exchanger.